Answer is: 10.164 grams of iron.
Balanced chemical reaction: 8Fe + S₈ → 8FeS.
m(FeS) = 16.0 g; mass of the compound.
M(FeS) = 87.91 g/mol; molar mass of the compound.
n(FeS) = m(FeS) ÷ M(FeS).
n(FeS) = 16 g ÷ 87.91 g/mol.
n(FeS) = 0.182 mol; amount of substance.
From chemical reaction: n(FeS) : n(Fe) = 8 : 8 (1 : 1).
n(Fe) = 0.182 mol.
m(Fe) = n(Fe) · M(Fe).
m(Fe) = 0.182 mol · 55.845 g/mol.
m(Fe) = 10.164 g.
